LOS ANGELES - Hollywood writers and producers broke off contract talks Wednesday night without a new deal, allowing the Writers Guild of America’s current pact to expire at midnight.

It wasn’t immediately known whether the writers will walk off the job. A call to a union spokesman was not immediately returned.

No new talks were scheduled for Thursday, the Alliance of Motion Picture and Television Producers said in a statement.

Both sides had resumed negotiations earlier in the day with the help of a federal mediator, and the writers submitted a revamped contract proposal with the hope of avoiding a strike.

Details of the proposal were not released, but it appears both sides couldn’t agree on whether to give writers more money from the sale of DVDs and the distribution of shows via the Internet, cell phones and other digital platforms.

Producers have said they wouldn’t agree to anything that would restrict their ability to experiment with new Internet and other digital delivery options for films and TV shows.

Calling it “the DVD issue,” AMPTP President Nick Counter said in a statement to the writers guild that it was blocking both sides from making further progress in their talks.

“We want to make a deal,” Counter said. “But, as I said, no further movement is possible to close the gap between us so long as your DVD proposal remains on the table.”

Members of the guild recently voted to authorize their first strike since 1988 if necessary. The union has set a meeting of its 12,000 members for Thursday night at the Los Angeles Convention Center.

Jonathan Handel, an entertainment lawyer at the Los Angeles law firm of TroyGould, said it was in the union’s interest to delay a walkout, perhaps by five days or more.

“The writers guild has two weapons: One is a strike, the other is the threat of a strike. It has no reason to toss that weapon away without using it for a bit,” said Handel, who served in the 1990s as an associate counsel for the guild.

Reality shows, news programs and reruns loomA strike by writers would not immediately impact film or prime-time TV production. Most studios have stockpiled dozens of movie scripts, and TV shows have enough scripts or completed shows in hand to last until early next year.

After that, networks might turn to reality shows, news programs and reruns to fill the prime-time airwaves. Late-night shows wouldn’t fare as well, since they are more dependent on current events to fuel monologues and other entertainment.

“The Daily Show with Jon Stewart” and “The Colbert Report” will almost certainly be forced into reruns by a lack of fresh skits and monologues if writers walk off the job.

“If the strike happens, we are very likely looking at repeats for both shows,” said Tony Fox, a spokesman for Comedy Central, which airs the shows starring Stewart and Stephen Colbert that lampoon political doings of the day.

“The Tonight Show with Jay Leno” could follow.

NBC declined to comment on what would be in store for the show. But a person with the network, who was not authorized to comment and spoke on condition of anonymity, said “Tonight” and other NBC late-night shows likely would have to resort to repeats with no writing staff to generate new material.

(NBC is a joint venture between Microsoft and NBC Universal.)

CBS declined comment on the possible fate of “The Late Show with David Letterman.”

During the last strike in 1988, Letterman, then host of NBC’s “Late Night,” and longtime “Tonight Show” host Johnny Carson initially went off the air but later returned as the walkout dragged on for more than five months.

NBC also declined comment on how “Saturday Night Live” might be affected in the weeks ahead but indicated this weekend’s show would air as planned.

On the movie front, studios are said to have as many as 50 projects ready to go into production. Several major studio projects reportedly are camera-ready, with scripts that could be filmed without requiring a guild member on hand for rewrites.

Some sectors would benefit from a walkout. Network news divisions could become beehives in a protracted strike, with networks calling on news magazines such as “Dateline NBC” to fill in programming gaps.

Reality TV producers are finding an even warmer welcome at networks, while independent filmmakers foresee the possibility of new distribution doors opening.